The feet of human beings are adapted for walking on relatively soft surfaces, such as grass, rather than on extremely hard surfaces such as asphalt or concrete. Constant walking on a hard surface such as concrete or asphalt can lead to foot, back and other problems. Accordingly, it is desirable to have a shoe outsole which is able to cushion the walk of a person wearing the shoe so that the deleterious effects of constant walking on pavement are mitigated, this being especially desirable in the vicinity of the heel and the ball of the foot which bear the brunt of the impact during walking and running. It is also desirable for a shoe outsole to be designed to permit at least some air circulation between the bottom surface of the shoe sole and the ground. Such air circulation has the effect of keeping the shoed foot warm in the winter and cool in the summer. Finally, it is advantageous that the outsole be shaped so that if the shoed foot is unintentionally turned to the outside or inside, the sole tends to redirect the shoed foot back toward the correct upright position.
Lombard et al, U.S. Pat. No. 3,100,354 discloses a shoe outsole wherein a depressed region extends continuously from the toe section to the back of the heel section. The primary disadvantage of this arrangement is that no support is provided in the middle of the shoe in the region of the shank. U.S. Pat. No. 4,096,649 issued to Saurwein discloses a shoe sole having a plurality of cut-out areas defined by flanges. The flanges, which define the contact surfaces of the sole, are too thin to provide effective cushioning. Again, moreover, there is little if any support provided in the shank region. U.S. Pat. No. 3,086,301 issued to Pastor discloses an outsole construction provided with an opening in the central ball region of the foot. In use, a cover is disposed over the opening, the intent being that the central ball region rest on the cover above the opening. In this arrangement, no cushioning is provided for the heel portion of the foot. Moreover, the space defined by the opening between the ground and the cover is of uniform height, and such an arrangement may not provide sufficient support for the ball region, which may sag into the opening. U.S. Pat. No. 2,555,590 issued to Johnson discloses an outsole having a heel portion including a chamber, which is, however, closed on the bottom surface of the sole. Consequently, air circulation into the chamber through the bottom of the sole is not possible. U.S. Pat. No. 1,690,115 issued to Huestis discloses an outsole having a multiplicity of irregularly shaped cut outs in the bottom surface thereof. These cut outs, however, do not provide the desired cushioning for the heel and central ball sections of the foot. Furthermore, there is a wide transverse depression extending across the middle of the sole and hence there is no support in the vicinity of the shank.
Thus, while the prior art discloses means for achieving some of the aforementioned desired properties of a shoe outsole, no known sole achieves all of the desirable properties. Accordingly, an objective of the present invention is a shoe outsole which simultaneously achieves the above-mentioned desirable properties.